|
Post by pinhead on Jan 31, 2018 10:04:22 GMT -8
Many people who come to the forum with experience in the "classic" tube-style heat exchange systems have never heard of or don't understand bell heat exchangers. I hope these drawings are useful to get the basic idea across.
|
|
|
Post by coastalrocketeer on Jan 31, 2018 12:02:29 GMT -8
Great post Pinhead! Thank you!
A useful mental tool in thinking about bell design is that you can "turn the design upside down" in your mind and imagine pouring water in the inlet port, watching it fill the bell, until it finally reaches the exhaust port and starts flowing out the chimney.
Hot gasses will want to fill the bell in roughly the same fashion when it is upright, if turbulence is sufficiently eliminated through the reduction of excess velocity of gas flow entering the bell.
|
|
|
Post by Vortex on Jan 31, 2018 16:02:20 GMT -8
Good idea Pinhead, unfortunately that doesn't seem to be a very good example of heat stratifying in a bell, as there's too much turbulence. I used to have the Energy2D model that you made that the gif is made from, and with a bit of tweaking I could get it to work well. (Whether it would behave the same in the real world is another story of course). The model was here: energy.concord.org/energy2d/double-bell2.html if anyone can still use it.
|
|
|
Post by coastalrocketeer on Feb 1, 2018 17:18:05 GMT -8
Agreed on the image not being a proper functioning (2d) bell...
The reason it shows gasses flowing accross the bottom and up and swirling around following the sides and top, is EXACTLY the "stratification disruptive" kind of gas flow pattern a bell is trying to prevent.
A bell should slow gasses on entry, enough that most of the gasses in the space are imparted little to no kinetic energy from that incoming gas flow...
|
|
|
Post by Vortex on Feb 2, 2018 3:18:07 GMT -8
That Energy2D model needs Java installed to work and my computer refuses to let me install it now. Shame as I used to like messing about with that model.
IIRC putting a small horizontal piece on the bottom left of both the right-hand walls stopped the rotation and allowed it to stratify nicely.
|
|